Security
Nothing leaves your machine.
SheetXL is not a service your data passes through. It is an engine you run. This page says where it runs, what it reports, what the agent can reach and how to tell us about a problem, in the form a security review asks for it.
Where it runs
For Agents
The engine runs inside the agent's process, in a local MCP server on 127.0.0.1, or in VS Code's own runtime. There is no SheetXL server between the agent and the file.
For Apps
The engine and the grid run in your users' browsers, served from your origin. Files open, calculate and save without a round trip to anyone.
For Servers
The library and the CLI run wherever Node runs: your containers, serverless functions or an air-gapped host.
What leaves the machine
Workbook contents: never
No cell, formula, file name or path is sent to SheetXL by any product, on any tier.
Usage statistics: Free and Pro agent plugin only
Feature use, error reports and license status, so we know what breaks and what is used. Business and Enterprise turn it off or point it at an endpoint you control.
License checks: on the machine
A key is validated locally against the host it was issued for. Activating or signing in contacts my.sheetxl.com once. Enterprise keys are offline-signed, so nothing needs to reach SheetXL, ever.
Website: aggregate, cookieless
The public site counts visits without cookies or client-side storage. The privacy policy lists the two providers.
The full list of what we collect, and why, is in the privacy policy.
What the agent can reach
Only the files it is given
The agent works on the workbook you open or name. The MCP server listens on localhost only and accepts no connections from the network.
Every change is reversible
Sandbox sessions, undo, a commit per change and an action log the agent and the person can both read. A wrong fix is rolled back, not patched over.
A person can watch
In VS Code the agent highlights the range it means and asks in the grid. Nothing happens off screen.
A local log, if you want one
An optional tool log, off by default, records each agent call to a file on your disk for your own review. It never leaves the machine.
Open and inspectable
The UI packages, the agent skills and the formula functions are MIT licensed on GitHub. The harness that scored the public benchmark is the one you install, not a private build. The engine is free to evaluate before any license is bought, so a review can run it on a workstation, watch its network and reach its own conclusion.
Certifications
SheetXL holds no SOC 2 report, because there is no hosted service to audit. The controls that matter are the ones on your machine: your disk, your network, your identity, your backups. SheetXL inherits them instead of asking you to trust ours.
Reporting a vulnerability
Email support@sheetxl.com with the subject “Security”. Security issues are first in the queue, ahead of every other report, and are handled in confidence. Please do not open a public issue for one.